Design and Construction

Armament

In early 1913, new pattern G. 329 trainer's telescopes of 2.5 power and 20 degree field were issued to these and many other capital ships, to replace the 5/12, 5/15 and 5/21 variable power G.S. telescopes that had previously been in use.[2]

Main Battery

The four 9.2-in guns Mark XI were arranged in two double Mark VII mountings fore and aft, able to elevate 15 degrees and depress 5 degrees.

The sights (also used in Lord Nelson class) were gear-worked with a range gearing constant of 32, graduated to 15 degrees (likely 16,300 yards for 2 CRH projectiles).[4] Range dials were provided for full charge at 2825 fps, reduced charge at 2425 fps, another at 2300 fps (possibly only for Minotaur, but likely for all) and 3-pdr sub-calibre and .303-in aiming rifle. MV was corrected by adjustable pointer to +/- 75 fps. The deflection was on a gearing constant of 82.66, 1 knot being 2.49 arc minutes, calibrated for 2875 fps at 5000 yards.

Drift was corrected by inclining the sight carrier 1.5 degrees. The side sighting position with sight lines 32.65 inches above the bore and 32 inches abreast whereas the central position was 38 inches abreast the bore.

Secondary Battery

The ten 7.5-in B.L. guns Mark II were arranged in five single Mark II mountings on each broadside, able to elevate 15 degrees and depress 5 degrees. They could fire 2 CRH or 4 CRH shells.

The sights (also used in Warrior class) were gear-worked with a range gearing constant of 49.28, graduated to 15 degrees (15,700 yards for 4 CRH, 14,200 for 2 CRH). Range dials were provided for full charge at 2800 fps, reduced charge at 2325 fps and 3-pdr sub-calibre and .303-in aiming rifle. MV was corrected by adjustable pointer to +/- 75 fps.

The deflection was on a gearing constant of 72.65, 1 knot being 2.70 arc minutes, calibrated for 2800 fps at 5000 yards. An arrow at 4.5 knots right deflection on the deflection dial was inscribed "Zero for sight testing".

Drift was corrected by inclining the sight carrier 2 degrees and by applying an additional 4.5 knots permanent left deflection when firing 4 CRH shells. The sighting lines with sight lines 11 inches above the bore and 32 inches abreast whereas the central position was 38 inches abreast the bore.A practice gun could be mounted ont he turret roof 65.12 inches above the gun bore.

A "C" corrector was fitted, presumably also a temperature corrector.

Other Guns

The mounting could elevate to 20 degrees and depress to 10 degrees, but though its sight could match the 20 degree elevation, the range dial was only graduated to 14.5 degrees (7,900 yards). This was fine, as there was limited fire control support provided for them and the weapons proved to have little effectiveness at the ranges where torpedo attack became deeply worrying.

The gear-worked sights were similar to the P IV type, but added a cross-connected trainer's sight. They had a range gearing contant of 54 and range dials for 2550 fps, 1962 fps, and 1-in and .303-in aiming rifles. The first series produced corrected for MV with detachable cams for 2600, 2575, 2550, 2525 and 2500 fps. The second series replaced these with an adjustable pointer for +/- 50 fps.

Fire Control

Rangefinders

Directors

In 1916, it was approved that the ships of this class should be retrofitted with directors as time, resources and opportunity permitted.[12]

Plans to outfit these ships with directors started in early 1915 but were slow to execute. Defence was lost before receiving hers, but in May 1915 her torpedo officer Hugh Cecil Robert Feilding was thanked by the Admiralty along with other officers for creating an extempore installation in the ship. The others, Minotaur and Shannon received their proper equipment in August and October 1918, respectively.[13]

The Elevation Receivers for the 9.2-in and the 7.5-in batteries were 4-in Triple Type with mechanical tilt correctors, Pattern H. 13. They could indicate elevations up to 15 degrees. The Small Type Training Receivers were pattern number 20 in "A" turret and S1 to S3 and P1 to P3, whereas "Y" turret and S4 and S5 and P4 and P5 had pattern number 21.[14]

Transmitting Stations

There were two, as one is called the fore T.S. in a 1915 source and the image above clearly can only pertain to this class.[15][16]

The 9.2-in turrets each had 2 bearing receivers that could be driven by a transmitter in the fore T.S. or by one of two special master transmitters mounted port and starboard in the foretop. A C.O.S. in the fore T.S. selected whether the 9.2-in group was driven by the transmitter in the fore T.S. or by one of the masters in the foretop. The fore T.S. had 3 repeat receivers wired off the 9.2-in and both 7.5-in groups to facilitate in changing over. The 7.5-in guns each had a single receiver, and the "special bearing transmitters" in the foretop also had a repeat receiver for their group. The overall bill of fare ran to:

2 special bearing transmitters, Graham's type

3 Barr and Stroud bearing transmitters (2 in foretop, 1 in fore T.S.)

19 bearing receivers:

4 in the two 9.2-in turrets

10 at the ten 7.5-in guns

3 repeats in the fore T.S.

2 repeats in the foretop

Three C.O.S. (one in fore T.S., and two in foretop)

It is not clear to me why "special" bearing transmitters were required, and how these were made compatible with the B&S receivers.

Flash Precautions

In early 1915 ships were called upon to report on what extemporary steps were considered necessary to prevent the ignition of charges in casemates, batteries and ammunition passages. The report from Defence read in part:

In this ship the comparative safety of the passages makes the danger less than in many other cases, and with the number of guns to be supplied it is better to accept some risk rather than reduce the rate of fire supply, which anything of real use in this line must do.[22]